As skeptics and enthusiasts banter back and forth over whether the biotech industry is seeing a bubble on Wall Street, a number of biotechs aren't waiting around for a definitive answer. In a busy week for IPOs in general, four biotechs are planning to go public this week. Seres Therapeutics leads the bunch with a $100 million offering to support its work on the microbiome. Microstent glaucoma devicemaker Glaukos, a medical device company, is also up alongside Cambridge, MA-based Catabasis and Germany's Pieris, the latest European outfit to land at Nasdaq in search of investors cash. Story